An expansion joint is formed by placing a mass of expansion material in a gap purposely provided between adjoining concrete structures for accommodating dimensional changes to the gap occurring as expansion and contraction due to temperature changes and/or seismic cycling and vibration. The expansion joint may also be damaged by the ingress of surface water but, particularly, by abrasion and compression forces generated by the passage of motorized vehicular traffic.
Expansion joints, particularly in sports stadiums, parking garages and airports are degraded when the expansion material must bear the wear and tear caused by contact with service vehicles, such as fork lifts or other vehicles used to transport supplies and equipment along corridors formed by concrete structures. The expansion material is often ejected from the gap between the concrete structures when the adhesion between the concrete material and the expansion material degrades allowing the ingress of water and development of damaging forces generated at freezing temperatures. A degradation to the expansion material may also occur by the passage of vehicular traffic, particularly when concrete structures form an uneven passageway resulting in impact loading on the structures by the traffic.
Elongated metal plates placed in an end-to-end relationship have been bolted to the concrete structure in an attempt to protect the expansion joint from damage due to pedestrian and vehicular traffic. Often, the metal plates become deformed and do not form a uniform seated engagement with concrete structures particularly where the traffic bearing upper surfaces of the adjoining concrete structures are irregular or undulating, which fails to provide the necessary uniform planar support for the metal plates. The metal plates are bent and distorted due to impact loading of traffic and acquire a state of looseness about their mounting bolts which degrades further when the mounting bolts eventually shear. Even before the metal plates become disjointed from the mounting bolts, the metal plates generate an annoying noise with each deflection against the adjoining concrete structures.
Additionally, it is widely known that the surfaces of concrete structural members are not always entirely uniform, and are often not produced with square or smooth surfaces. These concrete structural members are usually rough, often have substantially irregular or undulating gaps, or are missing entire chunks of concrete. Furthermore, there is often a vertical “offset” between two structural members, due to the settlement of concrete.
Therefore, a need exists in the art for an improved cover assembly to bridge gaps or openings between structural members to provide a smooth transition over the gap and to substantially reduce the trip hazard for pedestrians. There is also a need to provide a cover assembly to protect expansion joint material in a gap between structural members, such as concrete structures.